Summary
Creating image pixels for email open tracking involves embedding a 1x1 transparent pixel within the HTML of the email. When a recipient opens the email and their email client loads images, a request is sent to a server which logs the event. For click tracking, UTM parameters are appended to URLs, allowing tracking of clicks in analytics platforms like Google Analytics, or URLs are rewritten to redirect through a tracking server. While some ESPs (like SendGrid and Klaviyo) offer built-in tracking, careful implementation is required to avoid deliverability issues. Important factors to consider are sender authentication (SPF, DKIM, DMARC), sender reputation, and transparency in URL rewriting.
Key findings
- Pixel for Open Tracking: Email open tracking is generally achieved by embedding a 1x1 transparent pixel image in the email HTML. Upon opening and image loading, a request is sent to log the open event.
- UTM for Click Tracking: Click tracking relies on UTM parameters added to links or URL rewriting to redirect through a tracking server, enabling click data collection.
- Built-in ESP Features: Several Email Service Providers (ESPs), such as SendGrid and Klaviyo, offer automated open and click tracking.
- Deliverability Impact: Improper use of tracking pixels can negatively impact email deliverability, potentially leading to emails being flagged as spam.
Key considerations
- Authentication: Proper sender authentication (SPF, DKIM, DMARC) is crucial to prevent emails with tracking pixels from being flagged as spam.
- Sender Reputation: Maintaining a positive sender reputation is critical to ensure emails are delivered and not marked as spam.
- Transparency: If URL rewriting is used for click tracking, ensure redirects are transparent to maintain user trust and sender reputation.
- Alternative Options: If an ESP lacks built-in tracking, tools like Google Tag Manager can be used, although specific setup might be required.
- Client Limitations: Tracking pixels may not work if images are blocked by the email client or if the email is viewed in plain text, affecting tracking accuracy.
- Strategy for placement: Careful placement for the image tracking pixel within the email is required to improve the accuracy of email open tracking.
What email marketers say
11 marketer opinions
Creating image pixels for tracking email opens involves embedding a 1x1 transparent pixel (an HTML `<img>` tag) in the email. When the email is opened and images are displayed, the pixel is loaded, triggering a server request that logs the open event. For click tracking, UTM parameters are added to links to pass data to analytics platforms like Google Analytics, or URLs are rewritten to redirect through a tracking server. Platforms like SendGrid, Klaviyo and ActiveCampaign often have built-in tracking functionality.
Key opinions
- Open Tracking: Open tracking is achieved by embedding a transparent 1x1 pixel image in the email. When the email is opened and images are displayed, the image is loaded, triggering a server request which logs the event.
- Click Tracking: Click tracking can be done by adding UTM parameters to links or by rewriting the URL to redirect via a tracking server.
- Platform Features: Many email service providers (ESPs) such as SendGrid, Klaviyo, and ActiveCampaign offer built-in open and click tracking features, simplifying the setup process.
- Alternative Tools: If the sending platform lacks built-in tracking, tools like Google Tag Manager can be used, although specific setup for email tracking might be required.
Key considerations
- Image Blocking: Tracking pixels will not work if images are blocked by the email client or if the email is viewed in plain text, leading to inaccurate open rates.
- Pixel Placement: Strategic placement of the pixel within the email body is important for maximizing accurate open tracking.
- UTM Parameters: UTM parameters should be added to URLs to effectively track click-through rates and attribute website traffic to specific email campaigns.
- Transparency: When using URL rewriting, it's important to be transparent, redirecting users to the correct landing page to avoid damaging sender reputation.
- Client Variations: Consider testing across different email clients, as rendering of tracking pixels can vary.
Marketer view
Email marketer from Mailjet Blog explains that embedding a 1x1 transparent pixel within an email allows tracking of email opens. When the email is opened, the image is loaded, triggering a server request that logs the open event.
22 Jul 2024 - Mailjet Blog
Marketer view
Email marketer from HubSpot explains that Tracking URLs allow you to attribute traffic to the right source in HubSpot. These URLs are automatically generated when you create a link, and they'll help you understand which marketing efforts are driving the most traffic.
15 Jan 2025 - HubSpot
What the experts say
3 expert opinions
Creating tracking pixels and click tracking mechanisms requires careful implementation to avoid deliverability issues. Click tracking can be achieved through provided demo code, but it’s crucial to ensure sender authentication (SPF, DKIM, DMARC) and maintain a good sender reputation to avoid being flagged as spam. URL rewriting for click tracking must be transparent and ethical to prevent damage to sender reputation and blacklisting.
Key opinions
- Demo Code Available: Demo code is available for implementing click tracking, which is very similar to pixel tracking.
- Deliverability Impact: Tracking pixels can negatively impact email deliverability if not implemented carefully.
- Ethical Click Tracking: Click tracking methods, especially URL rewriting, must be implemented transparently and ethically.
Key considerations
- Sender Authentication: Ensure proper sender authentication (SPF, DKIM, DMARC) to mitigate the risk of being flagged as spam when using tracking pixels.
- Sender Reputation: Maintain a good sender reputation to further minimize the risk of deliverability issues.
- Transparent Redirects: Avoid redirecting users to unexpected destinations when using URL rewriting for click tracking to prevent damaging sender reputation.
Expert view
Expert from Email Geeks shares demo code for click tracking, noting that pixel tracking is very similar, and provides a link to the code.
29 Nov 2021 - Email Geeks
Expert view
Expert from Word to the Wise shares that click tracking methods, particularly URL rewriting, should be implemented transparently and ethically. Abusing click tracking, such as redirecting users to unexpected destinations, can damage sender reputation and lead to blacklisting.
13 May 2023 - Word to the Wise
What the documentation says
4 technical articles
Tracking email opens is achieved through web beacons (tracking pixels), which are 1x1 pixel images embedded in HTML emails. When an email is opened and the image is downloaded, the event is logged, capturing details like the email client and IP address. For click tracking, UTM parameters can be added to URLs to measure campaign performance in Google Analytics. Platforms like SendGrid and Klaviyo automate open tracking by embedding pixels and click tracking by rewriting URLs, providing analytics dashboards for campaign performance analysis.
Key findings
- Web Beacons for Open Tracking: Web beacons (tracking pixels) are used to log email opens by embedding a 1x1 pixel image.
- UTM Parameters for Click Tracking: UTM parameters added to URLs enable the tracking of clicks and campaign performance in Google Analytics.
- Automated Tracking: Platforms like SendGrid and Klaviyo automatically handle open and click tracking with embedded pixels and URL rewriting.
Key considerations
- Data Collection: Open tracking provides information about the recipient's email client and IP address.
- Performance Measurement: UTM parameters allow for the accurate measurement of email campaign performance.
- Analytics Dashboards: Some platforms provide detailed analytics dashboards to analyze campaign performance, leveraging automated tracking features.
Technical article
Documentation from Google explains how to create custom campaigns using UTM parameters to track clicks from emails. By adding parameters such as `utm_source`, `utm_medium`, and `utm_campaign` to URLs, you can accurately measure the performance of your email campaigns in Google Analytics.
28 Jan 2025 - Google
Technical article
Documentation from SendGrid explains that their platform automatically adds open and click tracking to emails. Open tracking works by embedding a pixel, while click tracking rewrites links to route them through SendGrid's servers for tracking purposes.
25 Apr 2024 - Twilio SendGrid
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